JP2011235994A - Automatic document feeder and image forming device provided with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic document feeder capable of reducing noise due to the contact of a document and a guide member caused after the entrance of the document to a curved conveying passage until an edge thereof passes through, and to provide an image forming device.SOLUTION: The ADF (automatic document feeder), which conveys a document separately fed from a document bundle on a document tray one by one aiming at a reading position while changing the conveying direction of the document about 180° through a curved conveying passage 53a, includes: the curved guide member 120 that forms a curved conveying passage 53a; a reading inlet sensor that detects the tip and rear ends of the document entering the curved conveying passage 53a; a conveying auxiliary device 130 that has a following movement roller 131 movable between an exposing position to expose on the curved conveying passage 53a and a retreating position to retreat from the curved conveying passage 53a, and a moving mechanism 132 that moves the following movement roller 131; a controller that controls the conveying auxiliary device 130 to move the following movement roller 131 between the exposing position and the retreating position according to the detection result of the reading inlet sensor.

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic document feeder and an image forming apparatus having the same, and more particularly to an automatic document feeder applied to an image forming apparatus such as a facsimile machine, a copying machine, and a multifunction machine.

  2. Description of the Related Art In recent years, an automatic document feeder is configured so that a document fed from a document placing table within a limited space is discharged to a sheet discharge tray positioned below the document placing table. The one that turns 180 ° (inverted) is the mainstream.

  However, in such an automatic document feeder, noise caused by contact between the document and the curved guide member at the turn portion becomes a problem as the thickness of the document to be conveyed increases.

  Conventionally, as an automatic document conveying apparatus for the purpose of suppressing such noise, a document conveying path and a double-sided surface are formed in a curved confluence portion where two document conveying paths, a document conveying path and a double-sided reading document conveying path, merge. A device is known that includes a driven roller that is in contact with a document to be transported and rotates with the transport of the document at the downstream end in the transport direction of the transport guide between the scanned document transport path (for example, a patent). Reference 1).

  In the automatic document feeder described in Patent Document 1, the frictional resistance between the document passing through the two document transport paths and the transport guide is reduced by the rotation of the driven roller, and the rubbing sound between the document and the transport guide is reduced. Can be reduced.

  In addition, an upper guide and a lower guide for guiding the sheet on the downstream side in the sheet conveying direction of the pair of conveying rollers for the purpose of preventing the so-called trailing edge noise caused by the contact between the sheet and the guide member. In the sheet conveying apparatus provided, a configuration in which the upper and lower guides are moved in the sheet thickness direction by a cam mechanism is also known (see, for example, Patent Document 2).

  In the conventional sheet conveying apparatus described in Patent Document 2, as the sheet is conveyed by the conveying roller pair, at least the upstream portion of the lower guide is moved so as to approach the nip line of the conveying roller pair. Sound can be reduced.

  However, in the conventional automatic document feeder described in Patent Document 1 described above, although the frictional resistance between the document passing through the curved junction and the conveyance guide can be reduced, the document enters the junction. In this case, the leading edge of the document collides with a part of the driven roller exposed on each document conveyance path, and a collision sound is generated. Further, when the trailing edge of the document passes through the driven roller, the trailing edge of the document collides with the conveyance guide due to the rigidity of the document that is curved and conveyed (the stiffness of the document), and so-called trailing edge noise is generated.

  As described above, in the automatic document feeder described in Patent Document 1, a collision sound generated when the document enters the curved document transport path, and a trailing edge splash sound generated when the document trailing edge passes through the driven roller. There was a problem that could not be prevented.

  Further, in the conventional sheet conveying device described in Patent Document 2 described above, although the trailing edge noise can be reduced, the sheet when the sheet enters the upper and lower guides, the upper and lower guides, There is a problem that it is not possible to reduce the impact noise and the rubbing noise caused by the frictional resistance generated between the sheet and the upper and lower guides until the sheet passes through the upper and lower guides.

  As described above, the conventional automatic document conveyance device and the sheet conveyance device as described in Patent Documents 1 and 2 have a rubbing sound caused by a frictional resistance generated when a document or a sheet passes through a curved conveyance path, Alternatively, paying attention to one of the trailing edge splash sounds, one of them is reduced, and the document (sheet) generated between the time when the document (sheet) enters the curved conveyance path and the time when the trailing edge passes. There is a problem that noise due to contact between the guide member and the guide member cannot be reduced.

  The present invention has been made to solve the above-described problems, and reduces noise caused by contact between the document and the guide member that occurs between the time when the document enters the curved conveyance path and the time when the trailing edge passes. An object of the present invention is to provide an automatic document feeder and an image forming apparatus capable of performing the above.

  In order to achieve the above object, an automatic document feeder according to the present invention separates and feeds documents one by one from a bundle of documents placed on a document table, and curves the document separated and fed by the conveying means. An automatic document conveying apparatus that changes a conveyance direction of a document by approximately 180 ° via a conveyance path and conveys the document toward a reading position, and includes a curved guide unit that forms the curved conveyance path, and an upstream of the curved conveyance path. Between the exposure position exposed on the curved conveyance path and the retracted position retracted from the curved conveyance path. And a conveyance assisting means having a rotating member rotatable by contact with the document and a moving mechanism for moving the rotating member, and depending on a detection result of the document detecting means, the rotating member is moved to the exposure position and the exposure position. Evacuation It has a configuration and a control means for controlling the transport assisting section to move to and from the location.

  With this configuration, the automatic document feeder according to the present invention controls the conveyance assisting unit so that the control unit moves the rotating member between the exposure position and the retracted position according to the detection result of the document detection unit. The rotation member can be exposed to or retracted from the curved conveyance path via the moving mechanism in accordance with the conveyance state of the document during the period from entry to passage of the document on the curved conveyance path.

  For this reason, the automatic document feeder according to the present invention exposes the rotating member on the curved conveyance path at a predetermined timing, so that the rotating member rotates by contact with the document passing through the curved conveyance path, and the guide means and the document The frictional resistance generated between the two can be reduced. As a result, it is possible to reduce the rubbing noise caused by the frictional resistance between the guide means and the document.

  The automatic document feeder according to the present invention prevents the collision between the rotating member and the document when the document enters the curved conveyance path, for example, by retracting the rotating member from the curved conveyance path at a predetermined timing. At the same time, when the document trailing edge passes through the curved conveyance path, it is possible to prevent the document trailing edge from colliding with the guide means. As a result, it is possible to reduce the collision sound and the so-called trailing edge sound when the document enters.

  Therefore, the automatic document feeder according to the present invention can reduce noise caused by the contact between the document and the guide means that occurs between the time when the document enters the curved conveyance path and the time when the trailing edge passes.

  Further, the automatic document feeder according to the present invention can prevent the document from being obliquely conveyed by reducing the frictional resistance between the document passing through the curved conveyance path and the guide means.

  Further, in the automatic document feeder according to the present invention, the control means moves the rotating member located at the retracted position to the exposure position at a predetermined timing after detecting the leading edge of the document by the document detecting means. The conveyance assisting unit is controlled, and after the trailing edge of the document is detected by the document detection unit, the conveyance assisting unit is controlled to move the rotating member to the retracted position at a predetermined timing.

  With this configuration, in the automatic document feeder according to the present invention, after the leading edge of the document is detected by the document detector, the control unit moves the rotation member positioned at the retreat position to the exposure position at a predetermined timing. Control. For this reason, when the original enters the curved conveyance path, the rotating member is positioned at the retracted position, so that the collision between the rotating member and the original can be prevented, and the collision sound when the original enters can be reduced. Further, after the original enters the curved conveyance path, that is, while the original passes through the curved conveyance path, the rotating member comes into contact with the original, thereby reducing the frictional resistance generated between the guide means and the original. The rubbing noise resulting from the resistance can be reduced.

  Furthermore, in the automatic document feeder according to the present invention, the control unit controls the conveyance assist unit so that the rotating member is moved to the retracted position at a predetermined timing after the trailing edge of the document is detected by the document detection unit. For this reason, when the trailing edge of the document passes through the curved conveyance path, the rotating member moves to the retracted position, thereby preventing the trailing edge of the document from colliding with the guide means, and so-called trailing edge noise can be reduced. .

  Also, in the automatic document feeder according to the present invention, the moving mechanism includes an arm member that rotatably supports the rotating member at one end and can rotate around a rotation fulcrum, and the rotating member includes the rotating member. An urging member that urges the other end of the arm member in the first rotation direction of the arm member that moves to the exposed position and a cam surface that can contact the other end of the arm member are formed. A cam member and a drive unit including a drive motor that rotationally drives the cam member, and the cam member rotates according to control of rotation drive of the drive motor by the control means, and the cam surface is By contacting the other end, the arm member rotates in a second rotation direction opposite to the first rotation direction against the urging force of the urging member, and the rotating member is exposed. It has a configuration to move from the position to the retracted position

  In the automatic document feeder according to the present invention, the drive unit may be a solenoid.

  An image forming apparatus according to the present invention includes the automatic document feeder according to any one of claims 1 to 4.

  With this configuration, it is possible to provide an image forming apparatus that can reduce noise caused by contact between the document and the guide member that occurs between the time when the document enters the curved conveyance path and the time when the trailing edge passes.

  The present invention provides an automatic document feeder and an image forming apparatus capable of reducing noise caused by contact between a document and a guide member that occurs between the time when the document enters the curved conveyance path and the time when the trailing edge passes. be able to.

1 is a schematic configuration diagram of an image forming apparatus including an image reading apparatus according to an embodiment of the present invention. It is a schematic sectional drawing of ADF which concerns on embodiment of this invention. It is a block diagram which shows the control structure of ADF which concerns on embodiment of this invention. It is a block diagram which shows the control structure of the 2nd reading part of ADF which concerns on embodiment of this invention. It is a figure which shows schematic structure of the conveyance assistance apparatus which concerns on embodiment of this invention, Comprising: (a) is a figure when a driven roller exists in a retracted position, (b) is a driven roller in an exposure position. FIG. 4A and 4B are diagrams illustrating a document conveyance state in the curved conveyance path of the ADF according to the embodiment of the present invention, where FIG. 5A is a diagram illustrating the time when the curved conveyance path is entered, and FIG. It is a figure which shows the inside, (c) is a figure which shows the time of a curved conveyance path | pass passage. It is a flowchart which shows the conveyance assistance control performed with ADF which concerns on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing an embodiment of an image forming apparatus provided with an automatic document feeder according to the present invention. In this embodiment, the image forming apparatus is applied to a copying machine 1.

  As shown in FIG. 1, the copying machine 1 includes an automatic document feeder (hereinafter simply referred to as ADF) 2, a paper feeding unit 3, an image reading unit 4, and an image forming unit 5.

  The ADF 2 includes a document tray 11 as a document table, and a transport unit 13 including various rollers. The ADF 2 transports the document placed on the document tray 11 by the transport unit 13 onto the slit glass 7, and passes the document that has been read by the image reading unit 4 through the slit glass 7 through the slit glass 7. After that, the paper is discharged onto the paper discharge tray 12. The ADF 2 is attached to the image reading unit 4 so as to be freely opened and closed via an opening / closing mechanism (not shown).

  The paper feeding unit 3 includes paper feeding cassettes 21 and 22 that store recording papers having different paper sizes, and various rollers that transport the recording papers stored in the paper feeding cassettes 21 and 22 to the image forming position of the image forming unit 5. The sheet feeding means 23 is provided.

  The image reading unit 4 includes a first carriage 25 on which a light source and a mirror member are mounted, a second carriage 26 on which a mirror member is mounted, an imaging lens 27, and an imaging unit 28. The image reading unit 4 irradiates light on a document passing through the slit glass 7 by a light source mounted on the first carriage 25, and from the document by each mirror member mounted on the first carriage 25 and the second carriage 26. The reflected light is folded, and the reflected light is imaged by the imaging lens 27 and read by the imaging unit 28.

  The image forming unit 5 includes an exposure device 31, a photosensitive drum 32, a developing device 33, a transfer belt 34, and a fixing device 35. The image forming unit 5 exposes the photosensitive drum 32 by the exposure device 31 based on the read image read by the imaging unit 28 to form a latent image on the photosensitive drum 32, and the photosensitive drum 32 by the developing device 33. In addition, different color toners are supplied and developed. The image forming unit 5 transfers the image developed on the photosensitive drum 32 by the transfer belt 34 to the recording paper supplied from the paper feeding unit 3, and then transfers the toner image transferred to the recording paper by the fixing device 35. The toner is melted to fix the color image on the recording paper.

Next, the ADF 2 will be described in detail with reference to FIG.
As shown in FIG. 2, the document tray 11 has a movable document table 41 and a pair of side guide plates 42. The movable document table 41 constitutes a substantially first half of the document tray 11 in the sheet feeding direction, and rotates in the directions a and b in the drawing with the base end as a fulcrum. As described above, the document tray 11 can adjust the front end of the document placed on the document tray 11 to an appropriate height by rotating the movable document table 41. .

  A proper feed position sensor 87 is provided above the front end of the movable document table 41. The proper paper feed position sensor 87 detects whether or not the front end of the original placed on the original placement surface is held at the proper paper feed position at an appropriate height.

  A home position sensor 88 is provided below the front end of the movable document table 41. The home position sensor 88 detects that the movable document table 41 is at the home position.

  Document length detection sensors 89 and 90 for detecting whether the orientation of the document is vertical or horizontal are provided in a substantially latter half of the paper feed direction of the document tray 11 so as to be separated in the feeding direction. Yes. As the document length detection sensors 89 and 90, a reflection type sensor that detects without contact by optical means or a contact type actuator type sensor may be used.

  The pair of side guide plates 42 are erected so as to position in the left-right direction with respect to the feeding direction of the document placed on the document tray 11. Further, one side of the pair of side guide plates 42 is slidable in the left-right direction with respect to the paper feeding direction, and is configured so that documents of different sizes can be placed thereon.

  On the fixed side of the pair of side guide plates 42, a set filler 46 that rotates by placing a document is provided. In addition, a document set sensor 82 that detects that a document is placed on the document tray 11 is provided at the lowermost part on the movement locus of the tip of the set filler 46. In other words, when the document is placed on the document tray 11, the document set sensor 82 rotates the set filler 46, and the leading end of the set filler 46 comes off from the document set sensor 82, and the document set on the ADF 2. The presence or absence of is detected.

  The transport unit 13 (see FIG. 1) of the ADF 2 includes a separation feeding unit 51, a pull-out unit 52, a turn unit 53, a first reading transport unit 54, a second reading transport unit 55, and a paper discharge unit 56. It is comprised by.

  The separation feeding unit 51 includes a pickup roller 61 disposed in the vicinity of the sheet feeding port, and a sheet feeding belt 62 and a reverse roller 63 disposed so as to face each other across the conveyance path.

  The pickup roller 61 is supported by a support arm member 64 attached to the paper feed belt 62, and is illustrated between a contact position where the pickup roller 61 comes into contact with the original bundle via a cam mechanism (not shown) and a separated position away from the original bundle. It moves up and down in the middle c and d directions. The pick-up roller 61 picks up several (ideally one) originals out of the originals stacked on the original tray 11 at the contact position.

  The sheet feeding belt 62 rotates in the feeding direction, and the reverse roller 63 rotates in the direction opposite to the feeding direction. The reverse roller 63 rotates in the reverse direction with respect to the paper feed belt 62 when the originals are double-fed. However, when the reverse roller 63 is in contact with the paper feed belt 62, or only one original is supplied. When the sheet is being conveyed, it is rotated along the sheet feeding belt 62 by the action of a torque limiter (not shown). As a result, double feeding of documents is prevented.

  The pull-out unit 52 has a pull-out roller 65 composed of a pair of rollers arranged so as to sandwich the conveyance path. The pull-out unit 52 performs primary abutting alignment (so-called skew correction) on the sent document according to the drive timing of the pull-out roller 65 and the pickup roller 61, and draws out and transports the document after alignment.

  The turn part 53 has a curved conveyance path 53a that curves from the top to the bottom of the conveyance path. Further, the turn portion 53 has an intermediate roller 66 and a reading entrance roller 67 which are a pair of rollers arranged so as to sandwich the curved conveyance path 53a. The turn unit 53 turns the document drawn and conveyed by the intermediate roller 66 by conveying the curved conveyance path 53 a, and conveys the surface of the document downward by the reading entrance roller 67 to the vicinity of the slit glass 7. It is like that.

In other words, the ADF 2 separates and feeds documents one by one from the bundle of documents placed on the document tray 11, and changes the transport direction of the documents by 180 ° via the curved transport path 53a. Then, the sheet is conveyed toward a reading position 7a described later. The intermediate roller 66 and the reading entrance roller 67 in the present embodiment constitute a conveying unit according to the present invention.
Details of the turn part 53 will be described later.

  Here, the conveyance speed of the document from the pull-out unit 52 to the turn unit 53 is set to be higher than the conveyance speed in the first reading conveyance unit 54. Thereby, the conveyance time of the document conveyed to the first reading conveyance unit 54 is shortened.

  The first reading conveyance unit 54 includes a first reading roller 68 disposed at a position facing the slit glass 7 across the conveyance path, and a pair of rollers disposed so as to sandwich the conveyance path after completion of reading. 1 reading exit roller 69. The first reading / conveying unit 54 conveys the surface of the document conveyed to the vicinity of the slit glass 7 while being brought into contact with the slit glass 7 by the first reading roller 68, and the document after the reading is completed by the first reading exit roller 69. Further, it is designed to be transported.

  The second reading / conveying unit 55 is disposed downstream of the second reading unit 101 in the conveying direction with the second reading roller 70 disposed at a position facing the second reading unit 101 that reads the back side of the document with the conveyance path interposed therebetween. And a pair of second reading exit rollers 71. In the second reading / conveying unit 55, the second reading unit 101 reads the back side of the original whose surface has been read. The document whose back side has been read is conveyed by the second reading exit roller 71 toward the paper discharge port. The second reading roller 70 serves as a reference white portion for acquiring shading data in the second reading unit 101 as well as suppressing the floating of the document in the second reading unit 101.

  In the case where double-sided scanning is not performed, the document passes through the second reading unit 101.

  The paper discharge unit 56 is provided with a pair of paper discharge rollers 72 in the vicinity of the paper discharge port, and discharges the original conveyed by the second reading exit roller 71 to the paper discharge tray 12.

  In addition, the ADF 2 is provided with an abutment sensor 84, a reading entrance sensor 86, a registration sensor 81, and a paper discharge sensor 83 along the conveyance path, and is used for conveyance control such as a conveyance distance and a conveyance speed of the document. It is like that.

  Further, a document width sensor 85 is provided between the pull-out roller 65 and the intermediate roller 66. The document width sensor 85 is composed of a plurality of light receiving elements arranged in the width direction of the document, and detects the document width based on the light reception result from the irradiation light provided at the opposite position across the conveyance path. Note that the length of the document in the conveyance direction is detected from the motor pulse by reading the leading edge and the trailing edge of the document by the abutting sensor 84.

Next, the control configuration of the ADF 2 will be described with reference to FIG.
As shown in FIG. 3, the ADF 2 includes a controller 100 that controls the entire ADF 2. In the present embodiment, the controller 100 is configured to execute conveyance assist control described later. The controller 100 in the present embodiment constitutes a control means according to the present invention.

  The ADF 2 includes a registration sensor 81, a document set sensor 82, a paper discharge sensor 83, a butting sensor 84, a document width sensor 85, a reading entrance sensor 86, a proper paper feed position sensor 87, and the like as sensors for inputting signals to the controller 100. A home position sensor 88 and document length detection sensors 89 and 90 are provided.

  The reading entrance sensor 86 is arranged upstream of the curved conveyance path 53a (see FIG. 2), and detects the leading edge and the trailing edge of the document entering the curved conveyance path 53a. It should be noted that the reading entrance sensor 86 in the present embodiment constitutes a document detection unit according to the present invention.

  Each of the above sensors is connected to the controller 100 and transmits a signal indicating a detection result to the controller 100.

  The ADF 2 is a motor that outputs signals from the controller 100 to control the driving of each part of the ADF 2, and the like. 97. Each of these motors is connected to the controller 100.

  The bottom plate raising motor 96 moves the movable document table 41 up and down, and the pickup motor 92 moves the pickup roller 61 up and down.

  The paper feed motor 93 rotationally drives the pickup roller 61, the paper feed belt 62, the reverse roller 63, the pull-out roller 65, and the intermediate roller 66, and the reading motor 94 is a reading inlet roller 67, a first reading roller 68, and a first reading. The exit roller 69 and the second reading exit roller 71 are rotationally driven, and the paper ejection motor 95 is configured to rotationally drive the paper ejection roller 72.

  The cam drive motor 97 is configured to rotationally drive a cam member 150 described later. The cam drive motor 97 in the present embodiment constitutes a drive motor according to the present invention.

  Each motor is controlled by the controller 100 based on the detection signal of each sensor described above. The ADF 2 includes a second reading unit 101 that reads the back side of the document, and the second reading unit 101 is connected to the controller 100.

  The copier 1 also includes a main body control unit 105 that controls the entire apparatus, and a main body operation unit 106 that performs various input operations and operation instructions. The controller 100 and the main body control unit 105 are connected via an I / F 107, and data such as a control signal is exchanged between the two. In the main body operation unit 106, the user can select whether the original reading performed by the ADF 2 is executed in the reading mode of the duplex mode or the simplex mode. Here, the user may set the same reading mode for all of the documents placed on the document tray 11 or may set different reading modes for each document. For example, out of a bundle of ten documents, the first and tenth documents can be set to the duplex mode, and the other documents can be set to the simplex mode.

  In the ADF 2 configured as described above, when the leading end of the document conveyed to the first reading conveyance unit 54 through the separation feeding unit 51, the pull-out unit 52, and the turn unit 53 is detected by the reading inlet sensor 86, the reading is performed. Before the leading edge of the document enters the nip portion of the entrance roller 67, the document transport speed is made the same as the reading transport speed, so that the document transport speed is reduced. At the same time, the reading motor 94 is driven forward (CW) to rotationally drive the reading inlet roller 67, the first reading roller 68, the first reading outlet roller 69, and the second reading outlet roller 71.

  When the leading edge of the document is detected by the registration sensor 81, the document is decelerated over a predetermined conveyance distance, and temporarily stops before the reading position 7a. At this time, the controller 100 transmits a registration stop signal to the main body control unit 105 via the I / F 107. Subsequently, when a reading start signal is received from the main body control unit 105, the document whose registration has been stopped is transported at an increased speed so as to rise to a predetermined transport speed before the leading end of the document reaches the reading position 7a. At the timing when the leading edge of the document detected by the pulse count of the reading motor 94 reaches the first reading conveyance unit 54, a gate signal indicating an effective image area in the sub-scanning direction on the first surface (front surface) is sent to the main body control unit 105. The document is transmitted through the first reading conveyance unit 54 until the trailing edge of the original comes off.

  When the reading mode is the single-sided mode, the document that has passed through the first reading conveyance unit 54 is conveyed to the paper discharge unit 56 via the second reading unit 101. At this time, when the leading edge of the document is detected by the paper discharge sensor 83, the paper discharge motor 95 is driven to rotate forward (CW) to rotate the paper discharge roller 72 counterclockwise. Further, at this time, the discharge motor pulse count from the detection of the leading edge of the document by the discharge sensor 83 reduces the driving speed of the discharge motor 95 immediately before the trailing edge of the document comes out of the nip of the upper and lower roller pairs of the discharge roller 72. Thus, control is performed so that the document discharged onto the discharge tray 12 does not jump out.

  When the reading mode is the duplex mode, the second reading unit 101 is detected at the timing when the leading end of the document reaches the second reading unit 101 by the pulse count of the reading motor 94 after the leading edge of the document is detected by the paper discharge sensor 83. On the other hand, a gate signal indicating an effective image area in the sub-scanning direction is transmitted from the controller 100 until the trailing edge of the document passes through the second reading unit 101.

Next, the control configuration of the second reading unit 101 will be described with reference to FIG.
As shown in FIG. 4, the second reading unit 101 includes a light source unit 111, a sensor chip 112, an amplifier 113, an A / D 114, an image processing unit 115, and a frame memory 116.

  The second reading unit 101 irradiates the original with light based on the lighting signal from the controller 100 by the light source unit 111, receives reflected light from the original with each sensor chip 112, converts it into an electrical signal, and outputs it. It is like that. The second reading unit 101 amplifies the electric signal output from each sensor chip 112 by the amplifier 113, converts the analog signal into a digital signal by the A / D 114, performs image processing by the image processing unit 115, and performs image processing. The signal subjected to the above is stored in the frame memory 116.

  In addition, the second reading unit 101 controls the output of a signal stored in the frame memory 116 based on a timing signal from the controller 100, and a signal output from the output control circuit 117 as a main body control unit And an I / F circuit 118 that outputs the data to 105.

  Next, the turn part 53 will be described with reference to FIGS. In FIGS. 5A and 5B, the intermediate roller 66 is not shown.

  As shown in FIGS. 5A and 5B, the turn portion 53 is provided with a curved guide member 120 that forms a curved conveyance path 53 a and a conveyance auxiliary device 130.

  The guide member 120 forms a curved conveyance path 53a with an inner guide 121 disposed inside the guide member 120, and guides a document conveyed through the curved conveyance path 53a. The guide member 120 in the present embodiment constitutes guide means according to the present invention.

  The conveyance assisting device 130 includes a driven roller 131 and a moving mechanism 132. The conveyance assist mechanism 130 in the present embodiment constitutes a conveyance assist unit according to the present invention, and the driven roller 131 constitutes a rotating member according to the present invention.

  The driven roller 131 is rotatably supported by the moving mechanism 132. Further, the driven roller 131 is exposed by the moving mechanism 132 to an exposed position (position shown in FIG. 5B) exposed on the curved conveyance path 53a and a retracted position (shown in FIG. 5A) retracted from the curved conveyance path 53a. Position). Here, when the driven roller 131 is in the exposure position, the driven roller 131 is rotated by contact with the document. On the other hand, when the driven roller 131 is in the retracted position, it is completely retracted from the curved conveyance path 53a and does not come into contact with the document.

  In the present embodiment, only one driven roller 131 is illustrated, but a plurality of driven rollers 131 may be arranged in the turn part 53 in a direction (document width direction) orthogonal to the conveyance direction, or curved conveyance is performed. A plurality of them may be arranged in the transport direction along the path 53a. Here, when a plurality of driven rollers 131 are arranged in the document width direction, a plurality of moving mechanisms 132 may be provided for each driven roller 131, or a plurality of driven rollers 131 are supported by one moving mechanism 132. It may be a thing.

  The moving mechanism 132 includes an arm member 140, an urging member 141, and a drive unit 142, and moves the driven roller 131 between an exposed position and a retracted position.

  The arm member 140 has one end 140a that rotatably supports the driven roller 131 and the other end 140b that is spaced apart from the one end 140a in the longitudinal direction. The arm member 140 is configured to be rotatable in a clockwise direction and a counterclockwise direction in the drawing around a rotation fulcrum 140c located at a substantially central portion between the one end portion 140a and the other end portion 140b. ing.

  In the present embodiment, when the arm member 140 rotates clockwise, the driven roller 131 moves to the retracted position. On the other hand, when the arm member 140 rotates counterclockwise, the driven roller 131 moves toward the exposure position. Then, the rotation of the arm member 140 is stopped at a position where the one end portion 140a side of the arm member 140 is in contact with a buffer material (not shown) provided on the guide member 120. At this time, the driven roller 131 is located at the exposed position exposed from the guide member 120 by a predetermined amount in the curved conveyance path 53a.

  The clockwise direction in the present embodiment corresponds to the second rotation direction in the present invention, and the counterclockwise direction corresponds to the first rotation direction in the present invention.

  The urging member 141 is disposed between the guide member 120 and the other end portion 140 b of the arm member 140. The urging member 141 urges the other end portion 140b so that the arm member 140 rotates in the counterclockwise direction (first rotation direction). The urging member 141 may be any urging member as long as it urges the other end portion 140b. For example, a compression coil spring may be used.

  The drive unit 142 includes a cam member 150 having a cam surface 150a that can be brought into contact with the other end 140b of the arm member 140, and a cam drive motor 97 (see FIG. 3) (not shown) that drives the cam member 150 to rotate. It is composed of

  As shown in FIG. 5A, when the cam surface 150a abuts against the other end portion 140b, the cam member 150 moves the arm member 140 in the clockwise direction against the urging force of the urging member 141 (second direction). The other end 140b is pressed so as to rotate in the rotation direction.

  Next, with reference to FIG. 6A to FIG. 6C, the conveyance state of the document in the curved conveyance path 53a will be described.

  First, as shown in FIG. 6A, the skew-corrected document P that is abutted against the pull-out roller 65 (see FIG. 2) is conveyed to the curved conveyance path 53 a of the turn portion 53 by the pull-out roller 65 and the intermediate roller 66. Is done.

  The leading edge of the document P conveyed to the curved conveyance path 53a is detected by the reading entrance sensor 86 when entering the curved conveyance path. At this time, the driven roller 131 is retracted to the retracted position. Therefore, the front end of the document P is guided by the guide member 120 and conveyed.

  Next, as shown in FIG. 6B, after the leading edge of the document P is detected by the reading entrance sensor 86, when the paper feed motor 93 is driven by a specified pulse, the moving mechanism 132 (FIG. 6) is driven by the drive of the cam drive motor 97. 5), the driven roller 131 moves to the exposure position. At this time, the document P is transported further downstream in the transport direction than when entering the curved transport path, and is passing through the curved transport path 53a.

  The document P passing through the curved conveyance path 53a is in contact with the driven roller 131. Further, the driven roller 131 in contact with the document P rotates as the document P is conveyed. For this reason, the document P does not contact the guide member 120 while passing through the curved conveyance path, and the frictional resistance between the document P and the guide member 120 is reduced.

  Next, as shown in FIG. 6C, when the original P passing through the curved conveyance path 53a passes through the curved conveyance path 53a, the trailing edge of the original P is detected by the reading entrance sensor 86. Then, after the trailing edge of the document P is detected by the reading entrance sensor 86, when the paper feed motor 93 is driven by a designated pulse, the driven roller 131 is driven by the cam drive motor 97 via the moving mechanism 132 (see FIG. 5). Moves from the exposure position to the retracted position.

  Specifically, according to the control of the drive of the cam drive motor 97 by the controller 100, as shown in FIG. 5A, the cam member 150 is rotationally driven, and the cam surface 150a is the other end 140b of the arm member 140. Abut. At this time, the arm member 140 rotates clockwise (second rotation direction) against the urging force of the urging member 141. As a result, the driven roller 131 moves from the exposure position to the retracted position.

  Note that the timing at which the driven roller 131 moves to the retracted position is preferably the timing immediately before the trailing edge of the document P passes through the curved conveyance path 53a, and the above-described designated pulse is set to match the timing. preferable.

  Accordingly, as shown in FIG. 6C, when the document P passes through the curved conveyance path 53 a, there is no step between the document P and the guide member 120, and the rear end of the document P becomes the guide member 120. There is no collision. Thereafter, the document P is conveyed toward the reading position 7a.

  Next, the conveyance auxiliary control executed by the controller 100 of the ADF 2 will be described with reference to FIG. This conveyance assist control is executed until the original P shown in FIG. 6 enters the curved conveyance path 53a and then exits the curved conveyance path 53a.

  As shown in FIG. 7, first, the controller 100 starts a pull-out operation for driving the pull-out roller 65 and the intermediate roller 66 by driving the paper feed motor 93 (step S1). At this time, the original P that has been abutted against the pull-out roller 65 and has been subjected to skew correction is conveyed to the curved conveyance path 53a.

  Next, the controller 100 determines whether or not the reading entrance sensor 86 has detected the leading edge of the document P (step S2). When the reading entrance sensor 86 does not detect the leading edge of the document P, the controller 100 repeatedly executes the process of this step.

  On the other hand, when the reading entrance sensor 86 detects the leading edge of the document P, the controller 100 determines whether or not the paper feed motor 93 has been driven by a specified pulse from the detection of the leading edge of the document P (step S3). If the controller 100 determines from the leading edge detection of the document P that the paper feed motor 93 is not driven by the designated pulse, the controller 100 repeatedly executes the processing of this step.

  On the other hand, when the controller 100 determines from the detection of the leading edge of the document P that the paper feed motor 93 has been driven by the designated pulse, the controller 100 moves the cam drive motor 97 to, for example, forward rotation (CW). ) Control to drive (step S4). As a result, the driven roller 131 moves to the exposure position and rotates in contact with the original P passing through the curved conveyance path 53a.

  Next, the controller 100 determines whether or not the reading entrance sensor 86 has detected the trailing edge of the document P (step S5). If the reading entrance sensor 86 does not detect the trailing edge of the document P, the controller 100 repeatedly executes the process of this step.

  On the other hand, when the reading entrance sensor 86 detects the trailing edge of the document P, the controller 100 determines whether or not the paper feed motor 93 has been driven by the designated pulse from the trailing edge detection of the document P (step S6). . If the controller 100 determines from the trailing edge detection of the document P that the paper feed motor 93 is not driven by the designated pulse, the controller 100 repeatedly executes the processing of this step.

  When the controller 100 determines from the trailing edge detection of the document P that the paper feed motor 93 has been driven by the designated pulse, the controller 100 moves the cam drive motor 97 to, for example, reverse rotation (CCW) to move the driven roller 131 to the retracted position. ) Control to drive (step S7). As a result, the driven roller 131 moves to the retracted position.

  Next, the controller 100 determines whether there is a next document to be conveyed following the document P (step S8). If the controller 100 determines that there is a next document, the controller 100 returns to step S2 and repeats the processes in and after step S2. On the other hand, if the controller 100 determines that there is no next original, this process ends.

  As described above, in the present embodiment, the controller 100 controls the conveyance assisting device 130 to move the driven roller 131 between the exposure position and the retracted position according to the detection result of the reading entrance sensor 86. In other words, when the controller 100 determines from the detection of the leading edge of the document P that the paper feed motor 93 has been driven by the designated pulse, the controller 100 controls the cam drive motor 97 to drive the driven roller 131 to the exposure position. For this reason, when the document P enters the curved conveyance path, the driven roller 131 is positioned at the retracted position, so that the collision between the driven roller 131 and the document P can be prevented, and the collision sound when the document enters can be reduced. Further, after the document P enters the curved conveyance path 53a, that is, while the document P passes through the curved conveyance path, the driven roller 131 contacts and rotates with the document P, so that the gap between the guide member 120 and the document P is reached. The generated frictional resistance can be reduced, and the rubbing noise resulting from the frictional resistance can be reduced.

  On the other hand, if the controller 100 determines that the paper feed motor 93 has been driven by the designated pulse from the trailing edge detection of the document P by the reading entrance sensor 86, the cam drive motor 97 moves the driven roller 131 to the retracted position. Control to drive. For this reason, when the trailing edge of the document P passes through the curved conveyance path 53a, the driven roller 131 moves to the retracted position, thereby preventing the trailing edge of the document from colliding with the guide member 120 and generating a so-called trailing edge sound. Can be reduced.

  Therefore, in the present embodiment, it is possible to reduce noise caused by the contact between the document P and the guide member 120 that occurs between the time when the document enters the curved conveyance path 53a and the time when the trailing edge passes.

  Further, in the present embodiment, the oblique conveyance of the original P can be prevented by reducing the frictional resistance between the original P passing through the curved conveyance path 53a and the guide member 120.

  In the present embodiment, the drive unit 142 that drives the moving mechanism 132 is configured by the cam member 150 and the cam drive motor 97. However, the present invention is not limited to this. For example, the drive unit 142 may be configured by a solenoid. Good.

  As described above, the automatic document feeder according to the present invention can reduce noise caused by the contact between the document and the guide member that occurs between the time when the document enters the curved conveyance path and the time when the trailing edge passes. For example, it is useful as an automatic document feeder applied to an image forming apparatus such as a facsimile machine, a copying machine, or a multifunction machine.

1 Copying machine (image forming device)
2 ADF (automatic document feeder)
7a Reading position 11 Document tray (document table)
53a Curved conveyance path 66 Intermediate roller (conveyance means)
67 Reading entrance roller (conveying means)
86 Reading entrance sensor (document detection means)
97 Cam drive motor (drive motor)
100 controller (control means)
120 Guide member (guide means)
130 Conveyance auxiliary device
131 Follower roller (rotating member)
132 Moving mechanism 140 Arm member 140a One end portion 140b The other end portion 140c Rotating fulcrum 141 Biasing member 142 Drive portion 150 Cam member 150a Cam surface

JP 2009-202987 A JP 2008-285300 A

Claims (5)

The originals are separated and fed one by one from the original bundle placed on the original table, and the originals separated and fed by the conveyance means are read by changing the original conveyance direction by approximately 180 ° through the curved conveyance path. An automatic document feeder for conveying toward a position,
Curved guide means for forming the curved conveyance path;
Document detection means that is disposed upstream of the curved conveyance path and detects the leading edge and the trailing edge of the document entering the curved conveyance path;
A rotating member that is movable between an exposure position exposed on the curved conveying path and a retracted position that is retracted from the curved conveying path, and that is rotatable by contact with the document; and a moving mechanism that moves the rotating member. Conveyance auxiliary means;
An automatic document comprising: control means for controlling the conveyance assisting means to move the rotating member between the exposure position and the retracted position in accordance with a detection result of the document detection means. Conveying device.   The control means controls the conveyance assisting means to move the rotating member located at the retracted position to the exposure position at a predetermined timing after the leading edge of the original is detected by the original detection means, and the original detection means 2. The automatic document feeder according to claim 1, wherein after the trailing edge of the document is detected, the conveyance assisting unit is controlled to move the rotating member to the retracted position at a predetermined timing. The moving mechanism includes an arm member that rotatably supports the rotating member at one end and is rotatable about a rotation fulcrum, and a first arm member that moves the rotating member to the exposed position. A biasing member that biases the other end of the arm member in the rotation direction, a cam member formed with a cam surface capable of contacting the other end of the arm member, and a drive motor that rotationally drives the cam member A drive unit comprising:
The cam member rotates in response to control of the rotational drive of the drive motor by the control means, and the arm member resists the biasing force of the biasing member by the cam surface coming into contact with the other end portion. The automatic rotation according to claim 1, wherein the rotation member is rotated in a second rotation direction opposite to the first rotation direction, and the rotation member is moved from the exposed position to the retracted position. Document transport device.   The automatic document feeder according to claim 3, wherein the driving unit includes a solenoid.   An image forming apparatus comprising the automatic document feeder according to claim 1.

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